FloatingWindow is a minimal macOS example app demonstrating how to create a floating window that can join any space (virtual desktop) on macOS. The window remains visible across all spaces and follows the cursor between multiple displays.

• Floating Window: The window uses .floating level and .canJoinAllSpaces collection behavior, so it appears above most other apps and on every virtual desktop (space).
• Transparent, Borderless UI: The window is borderless, transparent, and can be moved by dragging its background.
• Follows Cursor Across Displays: When your mouse moves to a different screen, the window jumps to the corresponding display, maintaining its position relative to the display.
• Simple SwiftUI Content: The window displays a simple label on a colored background as a demonstration.

• The app sets up a custom NSWindow:
  • styleMask: [.borderless, .fullSizeContentView]
  • window.level = .floating
  • window.collectionBehavior = [.canJoinAllSpaces, .fullScreenAuxiliary]
  • Transparent background, no title bar or buttons.
• A CursorMonitorManager observes mouse and space change events:
  • When the cursor moves to a new display, the window is repositioned to that display.
  • The window can be moved by dragging.

window = NSWindow(
    contentRect: NSRect(x: 0, y: 0, width: 200, height: 200),
    styleMask: [.borderless, .fullSizeContentView],
    backing: .buffered,
    defer: false)
window.isOpaque = false
window.backgroundColor = .clear
window.level = .floating
window.collectionBehavior = [.canJoinAllSpaces, .fullScreenAuxiliary]
window.contentView = NSHostingView(rootView: contentView)
window.isMovableByWindowBackground = true

• macOS 12.0+
• Xcode 13+
• Swift
• App must be set as an Agent (UIElement): To allow the floating window to behave as intended (e.g., no Dock icon, no menu bar), set the application to be an Agent in your Info.plist.
  Add the following key-value pair:

  <key>LSUIElement</key>
  <true/>

  This ensures the app runs as a background (Agent) application.

1. Clone this repository.
2. Open FloatingWindow.xcodeproj in Xcode.
3. Build and run the app.

You should see a small floating window labeled "Floating Window" that stays above other windows and follows your mouse between displays and spaces.

This project is provided as-is for educational purposes.

Author: wizardeur